Molding powder and the process of making same



Patented Feb. 28, 1933 UNITED STATES JAMES F. WALSH, OF EAST ORANGE, ANDMANUEL XIMENEZ, SOUTH PLAINFIELD',

NEW JERSEY, ASSIGNOR-S TO GELLULO ID CORPORATION, A CORPORATION OFJERSEY MOLDING- rownnn AND THE rnoonss on MAKING seivrn 7 No Drawing. I

This invention relates to a process of making molding powder andincludes the product resulting from the practice of the process.

There are various molding powders in use at the present time. However,as far as we are aware, many of these powders, such as considerablewastage. Some of these mold-' ing powders do not take die lmpresslons 1nfine detail nor reproduce a high gloss. Some are not satisfactorilysusceptible to finishing operations. Many cannot be formed into articlesof lasting colors both plain and variegated. Many more are notthermo-plastic, but after being once formed into shape cannot bere-worked or re-shaped.

An object of our invention, therefore, is the production of a novelmolding powder and a process of making same.

A further object of our invention is the production of a molding powderthat is moldable into articles that will not shrink, warp or check, norbe seriously affected by immersion in hot water; that hascharacteristics that permit trimmings, scrap and defective articles tobe repowdered and remolded, thus reducing Waste; that will take dieimpressions in finest detail; that will reproduce a high gloss; that issusceptible to finishing operations with satisfactoryresults that may beworked in lasting colors, both plain and variegated; and that isthermo-plastic.

A further object of our invention is the production of a molding powdercontaining cellulose nitrate, and wherein fire retardants are employedin order that the dry product Fur- Application filed February 26,1929.Serial 110.342,?16.

"may beground Without dangerof explosion.

The formula, of course, lselastlc to a considerable degree, andvariations may of; course-be made. We prefer the'following:

100 lbs. pyroxylin of about 10.80 to 11 .l0

percent nitrogen. 75 to 80 lbsJtricresyl phosphate or-' its equivalent.I 300 to 350 lbs. of gypsum filler in fine powder. f I V r ,7 Anydesired amount of pigment and/or coloring matter "for hue effects, andalso a sufiicient quantity of liquid solvent for com.- ,bmmthe'ingredients by mastication may be added. The use of pigments isobviously optional. In the event'of their use the gypsum filler ispreferably reduced a corresponding amount. All ofthe ingredients shouldbe mixed thoroughly by the aid of the liquid solvent. Said solvent maybe "any approprlate menstruum or menstrua, for'instance, ethyl alcohol,methyl alcohol, acetone, ethyl acetate, or ethyl-methyl ketone, alone'orin combinations. p I After conversion the mass is preferably workeddown, for instance in calender rolls, that are preferably heated, untilit is sub-' stantlally dry or has a solvent content of fronr 2 to 5percent. crumbly or flaky and is now further dried until practically allevidence of liquid solvent has disappeared. Then the material is Thepowdering operation is accomplished Without danger of fire or explosioninasmuch The composition becomes as the compositionis non-inflammable.This particular feature is highly desirable. Heretofore 'nitro cellulosecompositions could be ground only with great hazards. Grinding wasgenerally accomplished under water. With our composition grinding may beaccomplished without the aid of extraneous fire reducing agents.

The powdered product is now in condition for molding and may be utilizedeither in powdered form or may be formed into approximate shapes tofacilitate handling.

Although tricresyl phosphate is specified for the formula any equivalentsuch as triphenyl phosphate or other aromatic phosphate, or dibutylphthalate, dibutyl tartrate,

paraethyltoluol-sulphonamid, triacetin, or other camphor substitute maybe substituted therefor. A certain amount of celluloid scrap may be usedshould alow priced prodnot be desired inasmuch as no particular damageresults from the camphor or equivalent plasticizer in said scrap.However, the proportion of aromatic phosphate or other plasticizershould preferably be reduced in accordance with the proportion ofcamphor added. I

The filler is preferably neutral calcium sulphate, inasmuch as theneutral variety tends to stability in the product;

Hydrated calcium sulphate is preferred inasmuch as the water ofcrystallization is conducive to non-inflammability. I

Excellent molding powder is thus produced which molding powder has thequalities and characteristics enumerated. The

superiority of applicants composition will be readily appreciated bypersons skilled in the art.

It is understood that the foregoing detailed description is given merelyby way of illustration and I that many variations may be made, withinthe scope of the claim, without departing from the spirit of theinvention.

.Ve claim:

A molding composition in powderedforni 7 containing in close combinationapproximately 100 parts of pyroxylin of about 10.80 to 11.40 percentnitrogen, 7 5 to 80 parts of afomatic phosphate, and 300 to .350 partsofgypsum. r

In testimony whereof, we havehereunto.

subscribed our names. V JAMES'F. WALSH. MANUEL R. XIMENEZ.

